The present invention relates generally to an apparatus for providing a more effective and efficient gasifier apparatus which produces a high carbon ratio char product. More particularly, although not exclusively, the present invention relates to a rotating and movable bed gasifier apparatus.
Currently, there are many types of gasifier systems. Typically the gasification process is the primary energy generation means. Gasification generally takes materials, such as wood, coal, charcoal, agricultural residues, energy crops, municipal solid waste or other biomass materials, and gasifies them to make a “gas” used for power or electricity generation or other uses, such as heat production. A typical gasification system consists of a gasifier unit, a filtering system, and an energy converter.
Steam boiler/combustor units are also well-known, though their use for primary energy generation has been questionable for some time, mainly because of the harmful resultant emissions. A steam boiler/combustor creates high pressure steam used for power generation. Prior art systems apply steam boiler/combustor units as secondary energy generation means to gain energy and thus increase efficiency and reduce pollutants such as gasses produced during the gasification process. An example of this type of system can be found in U.S. Pat. No. 6,637,206 to Thiessen, which is herein incorporated by reference in its entirety.
One problem with fixed bed gasifiers is that there are inherent “hot spots” in the fuel, causing uneven gasifying. Some of these systems add moving fingers to the fixed bed to agitate the fuel to aid in the gasification process. The torque force on the fingers increases as the diameter of the fire tube holding the fuel increases. This limits the size of the gasifier which can be constructed. By creating too large a gasifier, these fingers or the shaft holding them bend and break during the agitation.
U.S. Pat. No. 2,226,927 to Rundstrom is an up-draft gasifier which uses a grate system which reciprocates vertically, up and down, within a fixed bed core to maintain an even flow of fuel and gas and allow for the removal of ash. A problem with these vertically reciprocating beds and fixed bed gasifiers is that the larger the gasifier, the more chance for uneven heating inside the bed gasifier and thus poor gasifying of the fuel.
A further problem with immovable gasifiers is that as ash is built up during the gasification process, fuel flow is reduced. This reduction in fuel flow can result in decreased efficiency of the gasification process.
A further problem with immovable gasifiers is that different fuels require various amounts of fuel flow in order to maintain a proper and consistent burn temperature. Without a proper volume of fuel flow to the fuel, the efficiency of the system is reduced.
Thus, in view of the foregoing, it is desirable to have an improved gasifying system that solves these and other problems of the prior art.
Therefore, the primary feature or advantage of the present invention is an improved gasifier.
Another feature or advantage of the present invention is the provision of a gasifier which reduces the size limitations in which a gasifier fuel mixer can be built.
Another feature or advantage of the present invention is the provision of a gasifier that more uniformly heats the material being gasified to improve efficiency.
Another feature or advantage of the present invention is the provision of a gasifier that improves fuel flow to the fuel.
Another feature or advantage of the present invention is the provision of a gasifier that preferably includes a rotating bed, is economical to manufacture, durable in use and efficient in operation.
Another feature or advantage of the present invention is the provision of a gasifier that preferably includes a movable bed for controlling the volume of fuel flow to the burning fuel.
These and the other features or advantages of the present invention will be apparent from the specification and claims that follow.